FIG. 8 illustrates an example of wireless microphones. The wireless microphone 100 is of handheld type and has a cylindrical grip portion 110 which is gripped by hand. The wireless microphone 100 is provided with a microphone unit 120 on one end (upper end) 111 of the grip portion 110 and with a transmitting portion 130 on the other end (lower end) 112 side of the grip portion 110. Although not shown, a secondary battery together with an audio signal output circuit, etc., are built into the grip portion 110.
As shown in FIG. 9A, the transmitting portion 130 includes a transmitting antenna 131. Preferably, the transmitting antenna 131 is provided on a bottom surface 113 side of the other end 112 of the grip portion 110 so that it is not covered by hand when the grip portion 110 is gripped by the hand.
In this example, the transmitting antenna 131 is configured with an elongated column 131a having electrical insulation and a coiled wire 131b wound therearound. As shown in FIG. 9B, on the bottom surface 113 of the grip portion 110 is provided an antenna cover 132 which covers the transmitting antenna 131. In this example, the antenna cover 132 is formed in a tongue shape with opposed two surfaces being generally flat and protruding from the bottom surface 113 of the grip portion 110.
The wireless microphone 100 is provided with charging terminals (a pair of positive side charging terminal and negative side charging terminal) for charging the secondary battery with the secondary battery built thereinto. As shown in FIGS. 9A and 9B, the positive side charging terminal and the negative side charging terminal 141 and 142 are located beside the antenna cover 132 within the bottom surface 113 of the grip portion 110.
Further, in this example, a battery common electrode terminal 143 and an ON/OFF control terminal 144 of the transmitting portion 130 besides the charging terminals 141, 142 are provided on the bottom surface 113 of the grip portion 110. Note that, if there is no need to differentiate these terminals 141, 142, 143, 144, they may be referred to collectively as microphone side terminal 140.
When the remaining amount of the built-in battery (secondary battery) becomes less than or equal to a predetermined level, the battery shall be charged. Many of the conventional chargers for wireless microphones are of standing type and they each have a recess into which the end of a grip portion is inserted and in which a power supply side terminal pin is provided corresponding to a microphone side charging terminal (see, e.g., Japanese Patent Laid-Open No. H8-163784).
However, the power supply side terminal pin, including a pin which expands and contracts due to a spring, is upstandingly provided such that it always protrudes from the bottom surface of the recess. Accordingly, they may be bent or broken if the external shocks are large enough due to rough handling, such as, e.g., throwing the grip portion into the recess.
Further, as the above-mentioned wireless microphone 100, in the model in which the antenna cover 132 is provided on the bottom surface 113 of the grip portion 110, the microphone side charging terminals may not be securely brought into contact with the power supply side terminal pins due to the presence of obstacles or antenna cover 132 thereof.